Conjugated proteins, including protein-polysaccharide conjugates, play a significant role in the structure and stability of many processed foods. One reaction that is particularly important in the processed foods industry is the Maillard reaction. The Maillard reaction is a nonenzymatic chemical interaction involving the condensation of an amino group and a reducing group. The reaction results in the formation of intermediates that can later polymerize to form brown, nitrogen-containing compounds known as mellanoidins.
There are three major stages to the Maillard reaction. In the first stage, glycosylamine is formed then undergoes a rearrangement into an Amadori compound. In the second stage, the amine group is lost and a carbonyl intermediate is formed. The carbonyl intermediate undergoes dehydration or fission to form highly reactive carbonyl compounds. In the final phase, the reactive carbonyl compounds react with other constituents of the food product to form melanoidins.
Products of the Maillard reaction are associated with positive attributes such as aroma, taste, and color. However, the reaction can also lead to reduced nutritional value, shortened shelf-life, and formation of undesirable compounds resulting in an off-taste.
Controlling the Maillard reaction is therefore critical in developing foods with improved nutritional value. Previous ways of producing protein-conjugates have not been effective for a variety of reasons. For example, dry incubation, which uses a lyophilization process combined with heating, is slow and does not provide adequate yields. Consequently, there is a need for more effective ways of controlling the production of conjugated proteins.